1. Field of the Invention
The present invention relates to a portable wireless terminal having a built-in antenna module, and more particularly, to a built-in antenna apparatus for a portable wireless terminal, which is designed with a planar inverted-F antenna (PIFA) and contributes to a slim and lightweight profile of the wireless terminal.
2. Background of the Prior Art
Recently, as portable wireless terminals, such as cellular phones, wireless notebooks, and terminals for a Personal Communication System (PCS), Digital Cellular System (DCS), Global Positioning System (GPS) and Personal Digital Assistant (PDA), have become increasingly popular, terminals with various new functions and designs have been introduced. The terminals are developed with small-sized, slim, and lightweight features in mind and at the same time are focused on providing a variety of functions to satisfy popular demand. Therefore, the design objectives for the terminals are focused on volume reduction while maintaining or improving the functionality.
Today, rod antennas (also known as whip antennas) and helical antennas are widely used, owing to their good omnidirectional properties. However, the rod antenna and the helical antenna, which protrude outward from the terminal, are easy to break when dropped. These factors degrade the external appearance and limit the portability of the terminal. Therefore, an antenna installed within the terminal (called a built-in antenna, an internal antenna, or an antenna) has had widespread use in recent times. Various efforts are being made to improve the performance and productivity of the built-in antenna. There are two types of built-in antennas in common use: a planar inverted F antenna (PIFA) module having a feed point and a ground point; and a chip antenna module, suitable for mounting on a ceramic dielectric substance and having a copper coil whose turns are adjusted according to the operating frequency of the terminal.
FIG. 1 is a perspective view of a prior art portable wireless terminal 100 and shows a slide type portable wireless terminal. Although the prior art exemplarily shows the slide type portable wireless terminal, it is not limited thereto but may be applied to a variety of terminals with a built-in antenna (e.g., a folder type terminal, a bar type terminal, a flip type terminal).
Referring to FIG. 1, the portable wireless terminal 100 includes a main body 110 and a slide body 120, which is slidable in a lengthwise direction of the wireless terminal 100 by a predetermined length. The slide body 120 is provided on a front side thereof with a display device 121. The display device 121 may be a color wide Liquid Crystal Display (LCD) module, preferably a touch screen panel. The display device 121 also includes a speakerphone device 122 installed at an upper side thereof, and at least one keypad assembly 123 installed at a lower side thereof. Preferably, the keypad assembly may include a navigation key button.
When the slide body 120 is opened on the main body 110, another keypad assembly 111 having a plurality of key buttons, preferably digital key buttons (in a 3×4 matrix), is exposed. In addition, another microphone device 112 is located at a lower side of the keypad assembly 111.
FIG. 2 is a rear perspective view of a prior art portable wireless terminal and shows the position of a radiator of a built-in antenna. Referring to FIG. 2, a battery pack serving as power supply means is installed on a rear surface 130 of the main body 110. In the conventional arrangement, the built-in antenna is installed inside the main body 110, as is indicated by a dotted line. In more detail, a plate type radiator is mounted at a predetermined height on a main board installed inside the main body 110. When the radiator is a PIFA type radiator having a dipole structure, it has a feed part and a ground part. The feed part is electrically connected to an RF connector of the main board and the ground part is electrically connected to a ground pattern formed on the main board. Accordingly, the radiator is fixed using an antenna carrier, or similar device, because the PIFA type radiator must be spaced apart from the main board a predetermined distance between the radiator and the main board.
However, when the antenna apparatus is installed inside the main body like in the prior art, the additional installation space of the antenna results in an increase in the volume of the terminal.